Sleep...my dear friend, where have you gone?

For all you more experienced moms out there, please tell me, when can I expect to sleep again?
My kids have been sleeping through the night since they were 5 and 8 weeks old individually. But the problem is that in our family of 5, and our house of 3 bedrooms, they have to share a room. They have chosen to sleep in the same bed. Regardless of how often we move one to the other bed, they seem to make their way back to each other. I am thrilled that they are so close that they want to be together but unfortunately this means their sleep patterns are tied together. If one wakes up, the both wake up. If one wets the bed, they both need to be cleaned up. This also means they are definitely going to share any germs and viruses because if one sneezes, the other gets sprayed. I think my DD would sleep later but my DS wakes her up every morning about 7am.
I think my DS would go to sleep earlier but my DD keeps him up playing til well after 9:30 (even though they are in bed at 8) every night. I know I am whining but I need some sleep. You can't ride this thrill ride called motherhood on 4-5 hours sleep. Then it seems the night they both crash hard and sleep through, I have some issue (like a cold or something) that keeps me awake. I really have a lot of admiration for those brave (if crazy) women who have as many as 4 0r more kids. They don't get to sleep for over 10 years or more. Maybe I like sleep too much. Maybe I should just say farewell to my friend. I just don't want to.
Sleep, my dear friend, I miss you terribly. Please don't forget me. One day, and I hope it is soon, we will be reunited........
Have a blessed day!!!